I. Technical Field
The present invention relates to a continuous band, of the type used to manufacture horticultural products and the like, by means of a longitudinal thermosealing or gluing of the band along its longitudinal edges, to convert it into a tube, also continuous, through which means of parallel welding and transversal cutting unitary bags are produced, in addition to the sealing and independisation thereof, bags which combine totally sealed plastic areas with mesh areas in order to allow the viewing and especially the aeration of the products contained therein.
The object of the invention is to provide a band that, while offering a high mechanical resistance for the bag, optimum protection against light for the products contained therein, greater bag printing capacity and higher machine-working speed due to the greater ease of welding of the sheets, said band incorporates a reinforcement in the bag handle gripping area that considerably reduces the sheet thickness required to support the load contained therein, substantially lowering product manufacturing costs and also having a beneficial effect on the environment.
II. Description of the Related Art
Certain horticultural products, such as oranges, lemons, potatoes, etc., have been marketed for a long time in plastic bags with a reticulated structure, which allow both aeration and direct viewing of the product.
Occasionally, the production of these bags is based on a mesh body that is closed by both ends after housing the product in its interior, which can optionally have one of said handle ends that facilitate the manual transport thereof after acquisition by the consumer.
On other occasions, the production of these bags is based on a continuous band which is laminated and closed upon itself to configure said tubular body, through a longitudinal thermo-welded seam, after which the aforementioned process is repeated, in such a manner that in these cases the conformation of the tubular body, i.e. the transformation of the continuous band into a laminated body, is carried out simultaneously with the filling and independisation of the bags.
In any case, the common problem with all these types of bags resides in the fact that this mesh body is unable to receive printed information, which is essential in most cases, as the product brand, characteristics, barcode, etc. must necessarily be established on the bag itself.
Although there are different solutions to this problem, they are all based on the fixation to the mesh bag, during the production process itself, of one or more continuous plastic strips, bearing the information that is fixed to the base structure of the bag by means of, for example, the conformation welds of the latter, continuous plastic strips that represent a complementary contribution of material to the bag, with the consequent increase in cost.
A more advanced solution is that offered by the Spanish utility model with application Ser. No. 9701734, of which the applicant itself is the holder, which describes a bag for horticultural products and the like, of the type mentioned in the second place, i.e. of the type having a structure based on a continuous band that closes upon itself to configure a tubular body, at the time of conformation and filling of the unitary bags to be produced therethrough.
Specifically, in this utility model the aforementioned band was envisaged as having a structure based on sealed or continuous plastic strips, alternating with mesh strips or bands, fixed by means of thermal welding to the former, in such a manner that, in a preferred example of an embodiment thereof, each, flattened and with a rectangular outline, offers a wide sealed and intermediate band on each of its sides and, on either side thereof, narrower mesh strips, in such a manner that the latter allows the aeration and viewing of the product, while the former allows the addition of printed information.
The applicant itself is also the holder of invention patent P200200427, which describes a continuous band for manufacturing bags comprised of a single continuous plastic sheet, the width of which coincides with that of the band itself, wherein, by means of a punching operation, a series of small areas that determine the existence of windows which, for example, may be aligned along the imaginary axis of the continuous band, in correspondence with what will become the axis of the front side of the bags, and on the side edges thereof, are eliminated.
Said windows are sealed with the collaboration of mesh fragments, which are fixed to the base sheet by means of thermal welding, throughout its perimeter, and which comprise the viewing and aeration areas of the internal product.
Even though this special structure represents greater homogeneity of the constituent material of the continuous band, a reduction in weight thereof, greater printing capacity and greater protection against light, it has the fundamental problem that, for the finally produced bag to have suitable mechanical resistance, the continuous plastic sheet must have a specific thickness, which implies associated manufacturing costs which it would be desirable to reduce.